Showing papers by "Ljubo Golič published in 1999"

Kristallstruktur und thermische Analyse von Hydroxylammonium-hexafluorotitanat(IV)-dihydrat und Hydroxylammonium-hexafluoroindat(III)

Abstract: Crystals of (NH3OH)2TiF6ċ2H2O have been isolated. The compound crystallizes in the monoclinic system (P21/c, No. 15) with cell parameters of a=6.203(1) A, b=10.057(1) A, c=7.464(1) A, and β=110.653(6)°. Reactions in the system In (OH)3– NH3OHF – HF have been investigated. Crystals of (NH3OH)3InF6 were isolated from aqueous solution. The compound crystallizes in the trigonal system (R3c) with a=b=c=7.764(2) A, α=β=γ=97.21(4)°. The thermal decomposition of both compounds was studied by TG and DSC analysis; the decomposition products were characterized by X-ray powder diffraction.

trans-Diaquabis(nicotinamide-N)bis(salicylato-O)copper(II)

Abstract: The Cu II atom in [Cu(C 7 H 5 O 3 ) 2 (C 6 H 6 N 2 O)2(H 2 O)) 2 is octahedrally coordinated by N atoms from two nicotinamide ligands [at 2.018(2) and 2.019 (2) A], by O atoms of two salicylate ligands [at 1.9656(19) and 1.9762(19) A], and by trans water molecules at considerably different distances [2.373 (3) and 2.894 (4) A]. Neutral monomeric units are held together by hydrogen bonds through water molecules and N and O atoms of the CONH 2 group of nicotinamide and carboxylate groups.

trans‐Bis(acetato‐O)bis(2‐amino‐6‐methylpyridine‐N)copper(II)

Abstract: In the title compound, [Cu(C 2 H 3 O 2 ) 2 (C 6 H 8 N 2 ) 2 ], the Cu atom is surrounded by two O atoms from the two mono-dentate acetate ligands and by two pyridine N atoms from the two 2-amino-6-methylpyridine ligands in a trans square-planar arrangement. The Cu-O and Cu-N distances are 1.952(2) and 2.046 (2) A, respectively. The complex has an inversion centre. The remaining carboxylate O atoms are located at 2.764 (3) A from the Cu atom, above and below this plane. The coordination around the Cu atom can therefore be described as (4+2). The pyridine ring is twisted 73.2 (1)° with respect to the plane formed by the Cu, the N and the more strongly bonded O atoms.

Recent Developments in Zeolite-like Materials Synthesis and Characterisation

Abstract: In the last few years considerable effort has been directed at the targeted synthesis of zeolites and zeolite-like microporous materials with predetermined physical and catalytic properties. With new computational techniques, it has become possible to design templates for the synthesis of specific microporous structures with desired pore size and connectivities. With regard to zeolite-like materials, much attention has been focused on transition metal containing systems, like zincosilicates, titanosilicates and various metalloaluminophosphates with a potential to generate specific redox conditions, in addition to Bronsted and Lewis active catalytic centres. Experimental determination of subtle structural features such as the nature and position of the catalytically active metal sites, and the location, orientation and disorder of templates, metals or complexes within the microporous hosts has become possible using new characterisation techniques, mostly based on X-ray diffraction and the use of synchrotron and neutron radiation sources. In situ studies of the kinetics of nucleation, crystal growth and phase transitions or catalyst activation and operation at elevated temperatures have remarkably benefited from the new high-flux and well-collimated third-generation synchrotron radiation sources, and from the advances in the X-ray detector design and data handling.